Hydrological Processes最新文献

{"title":"Differential Responses of Sap Flow to Environmental Factors Under Contrasting Rainfall Amounts During the Rainy Season in a Boreal Birch Forest","authors":"Yehong Tian,&nbsp;Xiuling Man,&nbsp;Zhipeng Xu,&nbsp;Tijiu Cai","doi":"10.1002/hyp.70017","DOIUrl":"https://doi.org/10.1002/hyp.70017","url":null,"abstract":"<div>\u0000 \u0000 <p>Sap flow dynamics are critical for understanding how vegetation consumes water and adapts to environmental stress. The response of sap flow in boreal birch secondary forests to rainfall variations during the rainy season, however, has been inadequately explored. Our study indicated that photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) are the primary drivers of sap flow density in birch trees across different diameter classes (<i>F</i>_ds: small trees, <i>F</i>_dm: medium-sized trees, <i>F</i>_dl: large trees). Soil water content (SWC) significantly reduces sap flow when it falls below the 0.18 cm³/cm³. Sap flow density increased with PAR and initially with VPD but plateaued at higher VPD levels due to saturation. A hierarchy of sap flow density was observed, with <i>F</i>_dl &gt; <i>F</i>_dm &gt; <i>F</i>_ds, each responding differently to PAR, VPD and SWC. With decreasing rainfall across rainy seasons, the influence of PAR on <i>F</i>_ds and <i>F</i>_dm weakened, while the influence of VPD strengthened. For <i>F</i>_dl, the impact of VPD peaked and then declined, while the influence of PAR showed an inverse pattern. In the dry season, <i>F</i>_dl was primarily driven by PAR and influenced by VPD and SWC, whereas <i>F</i>_ds was mainly controlled by VPD, with minimal effects from PAR and SWC. The response of <i>F</i>_dm to SWC was similar to that of <i>F</i>_dl, but it mirrored the response of <i>F</i>_ds to PAR and VPD. These findings suggest that sap flow in boreal birch forests may become increasingly susceptible to SWC stress as global climate change intensifies.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zero-Flow Dynamics for Headwater Streams in a Humid Forested Landscape","authors":"Jason A. Leach,&nbsp;Kara L. Webster,&nbsp;Danielle T. Hudson,&nbsp;James Buttle,&nbsp;Magali Nehemy","doi":"10.1002/hyp.70025","DOIUrl":"https://doi.org/10.1002/hyp.70025","url":null,"abstract":"<p>Much of our understanding on temporary headwater streams is from arid and sub-humid environments. We know less about zero-flow periods in humid headwater catchments that experience seasonal snow cover. Our study characterised the temporal and spatial patterns of zero-flow periods for forested headwater streams in a snow-dominated landscape. We used 36 years of streamflow data from 13 headwater catchments within the Turkey Lakes Watershed located on the Canadian Shield in Ontario, Canada, near the eastern shores of Lake Superior. These headwater catchments differ substantially in their number of May–November zero-flow days (0–166 days per year) despite being clustered in a small geographical area with similar geology, physiography and vegetation cover. The catchments also experience similar continental climatic conditions with relatively even precipitation inputs throughout the year (mean annual precipitation of 1210 mm/year). Inter-annual variability in the number of zero-flow days was primarily associated with May–November precipitation and evapotranspiration. Despite the large seasonal snowpacks that form in this region, the amount of snow did not appear to influence the extent of zero-flow periods. We found that between-catchment variability in zero-flow occurrences was related to differences in catchment area and catchment properties typically associated with greater groundwater influence. Our study suggests that occurrences of zero-flows in headwater streams can be highly variable even over small geographical regions and that flow permanence may be more sensitive to spring to fall weather conditions than the influence of snow due partly to the shallow soils typically found on the Canadian Shield.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observation and Simulation of Runoff During an Extreme Heatwave in a Glacial Basin on the Central Tibetan Plateau","authors":"Fei Zhu,&nbsp;Meilin Zhu,&nbsp;Yanhong Guo,&nbsp;Tandong Yao","doi":"10.1002/hyp.70014","DOIUrl":"https://doi.org/10.1002/hyp.70014","url":null,"abstract":"<div>\u0000 \u0000 <p>Glacier meltwater runoff during extreme heat waves is crucial for overall runoff replenishment; however, studies on the characteristics and mechanisms of extreme meltwater runoff on the Tibetan Plateau (TP) are relatively scarce. In this study, we combine field observations (hydrological, meteorological, and glaciological) with a precipitation runoff modelling system and glacier model (PRMSglacier) to investigate the characteristics of extreme glacier meltwater runoff and the associated energy balance and hydrological processes from October 2018 to September 2022 in the Sangqu Basin on the central TP. Good agreement was shown between observed and modelled total runoff and glacier-wide mass balance, with a mean Nash–Sutcliffe efficiency (NSE) of 0.74 and root-mean-square error (RMSE) of 22 mm w.e. The mean glacial meltwater runoff contributed 14% of the total runoff and snowmelt runoff 72.5% during the study period. Contributions of 21.3% and 59% for glacier meltwater and snowmelt runoff, respectively, during a heatwave from June to September 2022 thus indicated anomalously high glacial meltwater and snowmelt runoff in association with hot and dry meteorological conditions. Basin-scale energy balance results suggest that extremely low albedo and extremely high surface temperatures control the net shortwave and longwave radiation, leading to anomalously high melting of glaciers and snow. The hot and dry meteorological conditions from June to September 2022 primarily affected the source regions of the Yangtze River and Selincuo in Geladandong. This study highlights the importance of extreme glacial meltwater runoff to terrestrial water resources in association with frequent extreme heat waves.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishing the Hydrological Controls on Water Surface Area Variations in Oxbow Lakes","authors":"Joshua Ahmed","doi":"10.1002/hyp.70013","DOIUrl":"https://doi.org/10.1002/hyp.70013","url":null,"abstract":"<div>\u0000 \u0000 <p>Oxbow lakes are iconic fluvial landforms found in the floodplains of meandering rivers around the world. Their formation is associated with meander cutoff, a process that excises sections of river channel to optimise the downstream transmission of water and sediment. Overbank floods and conveyance through tie channels maintain some hydrological connectivity, but lakes are generally considered to passively infill until they are terrestrialised. Here, a suite of 64 lakes across two meandering rivers in the Bolivian Amazon Basin are used to demonstrate the hydrological dynamism of oxbow lakes by quantifying interannual variations in lake water surface area (WSA), using the modified Normalised Difference Water Index (mNDWI) on an archive of Landsat images, and evaluating the mechanisms controlling these changes using remotely sensed rainfall data and geospatial analysis. The majority of lakes (75%) decreased in size over the study period, while 25% increased in size. The results suggest that WSA variations are controlled by proximity to the active channel, with the magnitude of these variations being set by mechanisms of connectivity. Lakes connected by tie channels experienced WSA changes up to 3.9 times larger than lakes with no visible connection mechanisms. Incursion lakes displayed similar WSA changes to those with tie channels, while isolated lakes were found furthest from the mainstem and had the smallest range of WSAs. Chute lakes experienced a wider range of WSA change (−95% to +281%) and were more strongly controlled by mainstem proximity than neck lakes. Connectivity between the river and oxbow lakes is essential for governing lake hydrodynamics, and tie channels provide the critical conduit by which water can be transmitted deep into the floodplain.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating Spatial Heterogeneity of Karst Water Storage Capacity and Nonclosure of Underground Watersheds in Karst Hydrological Simulation","authors":"Zeling Ren,&nbsp;Binquan Li,&nbsp;Yang Xiao,&nbsp;Kuang Li","doi":"10.1002/hyp.70012","DOIUrl":"https://doi.org/10.1002/hyp.70012","url":null,"abstract":"<div>\u0000 \u0000 <p>Karst landforms interfere with the runoff generation and confluence process, resulting in generally poor hydrological simulation accuracy in karst watersheds. We proposed a new karst hydrological module, which has two cores. One is the karst water storage capacity distribution curve that represents the distribution of runoff generation thresholds in karst areas, and the other is the underground nonclosure coefficient that represents the nonclosure phenomenon of underground watersheds in karst areas. The new module was further coupled with the Xinanjiang rainfall–runoff (XAJ) model to establish a complete hydrological model for karst areas (referred to as XAJ-karst model). The sensitivity of the XAJ-karst model parameters was analysed using the Sobol method, and applied to a typical karst watershed in Guizhou Province, China, to test the model performance on daily and hourly time scales. In addition, we also explored the impact of dynamic changes in the nonclosure coefficient of underground watershed area in karst watersheds on model results. Results showed that the average value of Kling–Gupta efficiency (KGE) of the XAJ-karst model on the daily and hourly time scales was 0.85 and 0.77, respectively. In comparison with the XAJ model, the average KGE value of the XAJ-karst model on both daily and hourly scales improved by 10.8% and 6.4%, respectively, demonstrating better simulation accuracy. In addition, there is a underground nonclosure phenomenon in the Xiangyang watershed, and the actual area of underground watershed expands abruptly as the antecedent-precipitation increases to the critical value. Moreover, the water storage and hysteresis effects of the karst landform result in a certain hysteresis in water exchange between the underground watershed and adjacent watersheds.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative Classification of Spring Discharge Patterns: A Cluster Analysis Approach","authors":"Magdalena Seelig,&nbsp;Simon Seelig,&nbsp;Matevž Vremec,&nbsp;Thomas Wagner,&nbsp;Heike Brielmann,&nbsp;Jutta Eybl,&nbsp;Gerfried Winkler","doi":"10.1002/hyp.15326","DOIUrl":"https://doi.org/10.1002/hyp.15326","url":null,"abstract":"<p>Springs provide critical water resources that are sensitive to changing climate and catchment processes. In many regions, understanding the temporal variability and spatial distribution of spring discharge is therefore crucial for sustainable water management. Knowledge of these discharge characteristics, organised in a coherent framework, is essential for protecting spring water and preventing shortages. To establish such a framework, we conducted a comparative analysis of long-term discharge records from 96 springs across Austria. Based on discharge seasonality and autocorrelation, we derived a broad-scale classification through cluster analysis and explored associations between individual clusters. The identified similarities in discharge patterns were grouped into four distinct spring categories, each demonstrating common behaviour. To determine the main factors influencing discharge across these four groups, we compared their spatial and temporal patterns with regional climate and catchment characteristics. They align with physical drivers of spring discharge, including precipitation frequency and intensity, snow cover duration, and dominant aquifer type. As these factors were not included in the classification procedure, their alignment supports the validity of our statistical approach. We conclude that the quantitative information derived from this analysis provides a valuable complement to traditional spring classification schemes, which are often based on qualitative knowledge. Our proposed strategy refines these classification approaches, enhances objectivity and reproducibility, and promotes conformity across hydrological disciplines.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.15326","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Different Spatial Distributions of Vegetation on the Hydraulic Characteristics of Overland Flow","authors":"Chengzhi Xiao,&nbsp;Xiang Liu,&nbsp;Luqiang Ding,&nbsp;Nan Zhu,&nbsp;Zihan Wang","doi":"10.1002/hyp.70016","DOIUrl":"https://doi.org/10.1002/hyp.70016","url":null,"abstract":"<div>\u0000 \u0000 <p>Vegetation plays a crucial role in mitigating and controlling soil erosion caused by overland flow. However, variations in the hydraulic characteristics of overland flow induced by the spatial distribution of vegetation with different row and column spacings are often overlooked in existing literature, potentially leading to significant deviations in predicting these characteristics. In this study, 180 lab-scale runoff tests were conducted to clarify the hydraulic characteristics of overland flow considering six <i>α</i> (the ratio of the lateral distance of vegetation to stem diameter) levels, six <i>β</i> (the ratio of the slope distance of vegetation to stem diameter) levels, and three slope angles (<i>θ</i>) under five flow discharges (<i>Q</i>) conditions. The results show that the observed flow regime of overland flow belongs to the transition flow regions, shifting from slow to rapid as <i>α</i> and/or <i>β</i> increase. The friction coefficient and the proportion of frictional resistance in the total flow resistance increase with increasing <i>α</i> and <i>β</i>. The local resistance dominates the total flow resistance of bare glass slopes. The local resistance coefficient <i>ξ</i> decreases with increasing <i>α</i> and <i>β</i>, however, it initially increases and then decreases with increasing <i>θ</i>. The impact of <i>β</i> on the local resistance is greater for gentle slopes, whereas the impact of <i>α</i> is more significant for steep slopes. <i>ξ</i> exhibits a negative correlation with <i>Re</i> and the <i>ξ</i>-<i>Re</i> curves gradually level off as <i>α</i> or <i>β</i> increases, while they become steeper with increasing <i>θ</i>. A prediction model for the total flow resistance was established taking into account the combined effects of <i>Re</i>, <i>α</i>, <i>β</i> and <i>θ</i>, which provides better prediction performance than two other relevant models. The results obtained from this study provide valuable insights into the hydraulic characteristics of overland flow and offer clear guidance for vegetation management in controlling soil erosion on slopes with heterogeneous vegetation coverage.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 12","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142764267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling Seasonal Variability in Parameters Defining Volumetric Water Content in a Low Permeability Soil in Central Illinois: An Application of MODFLOW-6 and the Unsaturated Zone Flow Package","authors":"Michael P. Krasowski,&nbsp;Esra Gulsen,&nbsp;Allan E. Jones,&nbsp;Daniel B. Abrams","doi":"10.1002/hyp.70007","DOIUrl":"https://doi.org/10.1002/hyp.70007","url":null,"abstract":"<p>Increasing interest in solute transport phenomena in agricultural systems on a sub-annual basis necessitates a better understanding of seasonal changes in natural systems and how these changes can be incorporated into modelling. A better understanding of the seasonal timing of nutrient loading in tile drained agricultural systems in particular is essential for efforts trying to replicate or predict the occurrence of harmful algal blooms. Literature exists showing there are seasonal dynamics (freeze–thaw, plant-root processes, land management practices, etc.) that may cause changes in the hydraulic properties of the soil zone including hydraulic conductivity and porosity. To test whether these changes are important in an agricultural system, a MODFLOW-6 model using the unsaturated zone flow package was constructed. The simulation was comprised of separate, seasonal models to be run sequentially with each year being broken into a winter and summer seasons. As part of this architecture, model parameters representing soil hydraulic properties were allowed to vary by season. The model was calibrated against soil moisture observations at multiple depths using a genetic algorithm machine learning technique. The parameters of the sub-models were compared for the winter and summer seasons. Brook-Corey epsilon, saturated vertical conductivity, saturated volumetric water content and residual volumetric water content were found to be consistently different between the modelled summer and winter periods. A more traditional model which did not allow hydraulic properties to vary seasonally was also run and compared to the seasonal architecture and the seasonal architecture was found to improve simulation results. The hydrologic dynamics of the unsaturated zone—particularly in tile drained agricultural systems—control the residence time for water and solutes, which is critical for in-field chemical processes such as denitrification. This work has important implications for seasonal transport phenomena in agricultural systems and improving the simulation and prediction of harmful algal blooms.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microscopic Mechanism of Particle Clogging in Porous Media During Managed Aquifer Recharge: From X-Ray Computed Tomography (CT) Imaging to Numerical Modelling","authors":"Yang Xu,&nbsp;Xueyan Ye,&nbsp;Xinqiang Du","doi":"10.1002/hyp.70002","DOIUrl":"https://doi.org/10.1002/hyp.70002","url":null,"abstract":"<div>\u0000 \u0000 <p>Managed aquifer recharge (MAR) is a strategy within water resources management. However, issues related to clogging have hindered its implementation. The change in permeability of the medium is significantly influenced not only by the macroscopic characteristics of infiltration sand, such as heterogeneity and anisotropy, but also by its microstructural features, including pore structure, morphology and connectivity. Nevertheless, the interactions between fluid flow, particle migration and changes in permeability remain unclear. This study investigates the pore-scale response mechanisms between fluid flow and pore clogging using a non-destructive x-ray computed tomography approach. Our findings indicate that the decrease in permeability due to particle deposition occurs in stages, with particles preferentially accumulating in irregularly shaped pores. The changes in the permeability of the sand column exhibit a negative correlation with alterations in shape factor and tortuosity, while showing a positive correlation with the fractal dimension. As pores become clogged with particles, the increase in tortuosity leads to a longer flow path. Once the sharp edges of the irregular pores are filled with particles, the pore space becomes smoother and more uniform, and the fractal dimension of the pores gradually decreases with further clogging. Based on numerical modelling of particle movement and the clogging process in porous media, it was determined that pressure is greatest in clogged pores. When this pressure reaches a certain threshold, the particles that were previously trapped in the pores are flushed out, leading to uneven changes in normalised hydraulic conductivity and normalised concentration at the outlet. If the pressure is insufficient to dislodge the clogging particles, the water flow path is compelled to change, resulting in a gradual stabilisation of the clogging.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying Hydraulic Geometry and Whitewater Coverage for Steep Proglacial Streams to Support Process-Based Stream Temperature Modelling","authors":"A. L. Dufficy,&nbsp;B. C. Eaton,&nbsp;R. D. Moore","doi":"10.1002/hyp.70003","DOIUrl":"https://doi.org/10.1002/hyp.70003","url":null,"abstract":"<p>At-a-station hydraulic geometry (AASHG) relationships describe the dependence of a river's width, mean depth and mean velocity on discharge at a given location, and are typically modelled as power-law functions. They are often used when modelling stream temperature under unsteady flow conditions. Deriving AASHG relationships is challenging for steep proglacial streams due to the combination of complex morphology and velocity distributions, and rapidly varying flow. The objective of this study was to combine tracer injections with drone-based photogrammetry to derive AASHG relationships for a steep proglacial channel and to quantify whitewater coverage and its relationship with discharge to support process-based stream temperature modelling. Velocity–discharge and width–discharge relationships were reasonably well characterised using power-law functions, but varied amongst sub-reaches. Whitewater coverage as a fraction of total stream surface area generally exceeded 50% for the range of flows sampled, and exhibited a statistically significant positive relationship with discharge, which varied amongst sub-reaches. For the range of flows captured during drone flights, the relationship could be represented by a linear function. However, an asymptotic model would be required to extend the relationship to higher flows. The magnitude of whitewater coverage indicates that the albedo of the stream should be substantially higher than values typically used in stream temperature models, and the relationship with discharge means that ongoing glacier retreat, and the associated reduction in summer discharge, should result in lower albedo and higher downstream warming rates, reinforcing the effects of decreasing velocity and mean depth as flows decline.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"38 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}